Rotary-wing aircraft



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ROTARY-WING AIRCRAFT Filed Nov. 21, 1950 11 Sheets-Sheet 7 Sept. 29,1953 Filed NOV. 21, 1950 J. A. J. BENNETT ET AL ROTARY-WING AIRCRAFT 11Sheets-Sheet 8 Sept. 29, 1953 J. A. J. BENNETT ET AL 2,553,778

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ROTARY-WING AIRCRAFT Filed Nov. 21, 1950 11 Sheets-Sheet 11 mirneyhatented Sept. 29,

ROTARY-WING AIRCRAFT James Allan Jameson nennmjoerrards Cross, andArchibald Graham Forsy'th, Cheam, England, assignors to The FaireyAviation Company limited, Hayes, England Application November 21, 195 0,Serialfio. IQBJTGB InGreat Britain September 7, 19,49

1 1"0 clams. This invention relates to rotary W ng aircraft, and has foran object the simplification and reduction or elirriina-tion "ofmechanical 'transmis sion and a simplification of control operation inght Helicopter rotors in the past have been limited in size to adiameter of about 50 ft., .and large helicopters have necessitated the-employment fof two or more rotors, despite the complexity introducedthereby. The rotor torque in both single rotor and multi-rotorhelicopters has required the simultaneous operation of four controls,ne-

cessitatin'g a high degree of concentrated attention by the pilot. Heavytransmissions have resulted in high maintenance costs and :uneconomicuseful load.

In this specification the term rotor, where it is employed, signifies anumber of rotatable blades constituting a sustaining rotary wing system,and is not intended to refer to the rotor of a turbine. Similarly, theterm bla'de signifies one of the members of such a system, and is notintended to refer to the blade or a turbine.

According to the invention the proposed rotary wing aircraft has two ormore independent turbocompressor driven propellers arranged to beoperable for forward propulsion and a sustaining rotor arranged to bepowered by jet units on the tips of the rotary wings, the rotor hubbeing prolvide'd with a distributor fed from any or all of theturbo-compressor units and serving all the jet units of the rotor. I

According also to the inventionthe proposed rotor craft comprises asustaining rotor, two outboard propellers, and two power units in whichthere is no mechanical transmission to the rotor, and no mechanicalinterconnection between the two power units, the said rotorcraft beingcapable of operating either as a helicopter (in which case the rotor ispowered by jets on the tips of the rotary wings and the propellers areat finepi't'ch) or as a gyroplane (in which case the rotor isautorotative and the propellers are powered separately by power units)or said rotorcraft may be flown employing the gyrodyne principle ofdistributin the power between rotor and propellers.

According further to the invention the proposed rotary wing aircraftcomp'rises a sustaining rotor, two propellers for forward propulsion"and two power units mounted at the outboard ends of stub Wings, therebeing no mechanical power transmission mechanism between the power unitsand the rotor and no mechanicalinterconnection between the power unitsthemselves,

each of the power units including a turbo-driven 2 an compressor having'va lved connection with jets mounted at the tips or the rotar wings,the valved connections being arranged to enable the output of the aircompressors to be divisible in variable ratio between the jets at thetips of the rotary wings and the turbines, whereby a suiiicientproportion of said output may befrieiivered to the jets at th tips orthe rotary wings to drive the rotor for vertical flight, 'or "the wholeof said output maybe delivered to the turbines to enable the propellersto be employed for forward flight, the rotor then being auto-"mar a, orsaidout'p'ut may be distributed in any other desired ratio between thejets at the tips of the rotary wings and the tiirbines. v

Throttle valves in the connections between the compressors and the jetsat the tips of the rotary wings 'rnay cooperate with constant speedgovernors, one "for each power unit, so that as the power falls on atsaid jets it is transferred fto'the propellers. I v p The rotor craftmay comprise a sustaining r'o'tor and two independent outb'oarclpropellers, wh'ereby control of the aircraft in yaw, indepe'n'de'ntly offorward speed, may be obtained differential control of the pitch of thepropellers, or, constant speed unit's -are provided, by diner-I'en'ti'al throttle control of the separate power pr ms driving thepropellers. I v

"I'he rotorc'raft may comprise a sustaining rotor and two independentoutboard propellers driven by separate power units whereby, infth'eevent of failure of either power unit, the pitch of the operativepropeller maybe reduced to give substantially zero thrustand theoperative unit may be utilized to provide 'air flow for the operation ofjets at the tips .of the rotary Wing's.

The constant speed govern rs may be connected with variable pitchcontrol mechanism for the propeller blades fso arranged that when thejets at fthe tips of the rfotar y wings are in use for ver'ti'cn flightthe ropeller blades are set at substantially zero pitch and, when "thnew to said jets is out off gradually and the flow .to

the turbines is increased, the pitch of the pro pellei' meat-s ismeter-sea i'cairespondirien Turin-1 the desired change or newdistribution is attained.

'-I 'he hub of the rotor may be provided with a distributor arranged tobe fed from either for Figure '7 is a side elevation, partly sectioned,of l the rotor head, on an enlarged scale,

Figure 8 is a diagrammatic representation of the pilot's controls forthe three-engined installation,

Figure 9 is a diagrammatic side elevation of the pilots control leversset for hovering flight, Figure 10 is a diagrammatic plan of the leversin this position, showing the gating thereof,

Figure 11 is a fragmentary front elevation of a differential for anoutboard engine control lever,

Figures 12 and 13 are views corresponding with Figures 9 and 10, butwith the control levers set for the start of the change from hovering toforward flight,

Figures 14 and 15, and 16 and 17, are corresponding views showing thecontrol levers set for further stages in the change from hovering toforward flight, and

Figures 18 and 19 are corresponding views showing the control leverswith all controls closed.

Referring to Figures 1 to 4, which show a twoengined aircraft, theaircraft ID has a large diameter sustaining rotor II mounted on a pylonI2 located in the plane of symmetry, with stub wings I3, I4 extending oneach side of the pylon I2. At the outboard ends of the stub wings thereare power units I5, I6, each comprising a turbine II driving an aircompressor I8 and a tractor variable pitch propeller I9.

The blades of the rotor I I are formed with internal ducts 20 fed from adistributor 2I in the pylon I2, and provided at their outer ends withjet units 22 arranged to discharge a flow tangentially for driving therotor II. Fuel supply and ignition services (not shown) are led from thepylon I2 through the distributor 2| to the ends of the rotary wings.

From each compressor I8 there extends a duct 23 for compressed airconnected with the input side of the distributor 2I and provided with anair valve 24 and a constant speed governor 19a associated with the powerunit I5 or I6.

Non-return valves 25 are provided where the ducts 23 communicate withthe distributor 2I, so that failure of one of the compressors does notaffect the delivery of the other to the rotor I I.

For vertical flight, the propellers I9 are set at substantially zeropitch, and the air valves 24 permitting air to be fed to the distributor2I are opened, so that the necessary amount of air is tapped from thecompressors I8.

When, for forward flight, the sustaining rotor I I is to be changed overto the autorotative condition, the controls (not shown) are arranged sothat as the air supply is cut off from the jet units 22 it istransferred to the combustion chambers of the turbines II, therebyraising the power to be absorbed by the propellers I9. When the airvalves 24 are fully closed each power plant delivers the whole of itsoutput-power to the associated propeller I9; the change-over is achievedby the air valves 24 in the air ducts 23 cooperating with the constantspeed governors I9a. As the air valves 24 are gradually closed, thepower applied to the propellers I9 is increased, and the constant speedunits increase the pitch of the propellers I9 until the desired forwardspeed is attained.

Figures 5 to 19 show a three-engined aircraft, in more detail than hasheretofore been described, which may broadly be considered as the sameas the two-engined aircraft, but with a third engine in the fuselage.Like reference numerals are used for like parts.

As will be seen from Figures 5 and 6, the third turbine 26 is located atthe foot of the pylon I2 and drives a compressor 21, which delivers airthrough a duct 28 first rearwardly and then upwardly through the pylonI2 to the distributor 2I through a non-return valve 25. Means (notshown) are provided for tapping either of the ducts 23 from the outboardengines to feed the combustion chambers of the turbine 26. In this wayinstantaneous starting of the turbine 25 may be obtained during forwardflight with autorotation, when the turbine 26 is normally at rest.

Figure 7 shows in greater detail the construction of the rotor head. Theducts 23, 28 lead to the non-return valves 25, each of which has a valvemember 29 urged by a spring 30 against a seating 3i. Short pipes 32 leadthe air up through the rotor head body 33 to openings 34 through whichit passes to a plenum chamber 35 within the rotor head casing 36. Thiscasing carries the blades of the rotary wing II and is rotatable onbearings such as 31, 38 about the rotor head body 33. Pressure air thuspasses from the ducts 23 or 28 through the valves 25, pipes 32, andopenings 34 to the plenum chamber 35 and thence to the ducts 20. If anyof the compressors fail, its associated valve 25 shuts, therebypermitting the pressure in the plenum a chamber 35 to be maintained.

The arrangement of controls may be seen schematically in Figure 8. Theoutboard power units I5, I6 drive controllable pitch constant speedpropellers I9 and have power throttles 39, 40 each connected, throughdifferential assemblies M, 42, with throttle control levers 43, 44respectively. Also connected with the differentials 4|, 42 are linkagesindicated at 45, 45 connected at their other ends with a rudder bar 41pivotally mounted at 48. Operation of the rudder bar 4'! enables thepower throttles 39, 40 to be operated independently of the throttlecontrol levers 43, 44.

The air valves 24 are interconnected by a linkage indicated at 49 andcontrolled by an air supply valve control lever 50. The lever 50 isinterconnected with the throttle control levers 43, 44 in a manner whichwill become apparent on reference to subsequent figures.

The centre turbine 25 has a power throttle 5| connected by a linkage 52with a throttle control lever 53. This has no interconnection with anyof the other controls.

Figures 9 to 19 show the control levers in different positions, thestructure being shown in somewhat greater detail. In Figures 9, 12, 14,16 and 18 the control levers are shown in side elevation pivoted about acommon axis 54, this axis also being indicated schematically in Figure 8in broken lines. As in these figures the outspasms '5 board power unitthrottle control levers 4,3, 44 move togethenonly thecontrol lever 44 isshown.

The differential assembly 42 is shown ir-rFigures 9 and 11. A link 55from the -control lever 44 actuates a lever arm '56 and through it acrown wheel 51, while the rudder bar linkage 46 actuates a similar leverarm 5 8 and .crown Wheel .55 on the opposite side of the diiferentialassembly. Between these'crown wheels is .a carrier '60 carrying pinions64,, $2 and a lug 63 actuating a linkage 64 connected with and operatingthe power throttle 40 of the power unit I5. I

The air supply valve control lever 50 is interconnected with thethrottle control levers 43, 44 by means of a gate 65 and a gating bar66, the operation of which will be apparent from Figures 10, 13, 15, 17and 1'9.

The operation of the control levers in flight is as follows:

During hovering flight the levers are as shown in Figures 9 and 10. Allthe power units are running at equal throttle settings, giving onlyenough power at the propellers .19 to stabilize the aircraft attake-off. The remainder of the power from the outboard power units,controlled by the air valves 24, is available as pressure air to therotor jets, and this, together with the full complement of air from thecentre compressor 21, provides the required power for the rotor H.

In the event of one power unit failing, suflicient power in theremainder is available to restore the required power to the rotor M.This is accomplished by moving the throttle levers into the fully openposition indicated in broken lines at 6.1.

The changeover from hovering to forward flight is achieved in threestages. In stage 1, the control lever 50 is moved to the position shownin Figures 12 and 13, the position of the throttle levers remainingunchanged. The power to the rotor II is decreased, and the power to thepropellers I9 is increased sufficiently to give enough power for therequired forward speed. At this stage the pilot may return to hoveringif desired b returning the lever 50 to the position shown in Figure 9.

In stage 2, the centre throttle control lever 53 is moved to the fullyclosed position, as shown in Figures 14 and 15.

The outboard throttle control levers 43, 44 and the air supply valvecontrol lever 50 are left unchanged. The aircraft is now operating onthe outboard power units only, the propellers I!) being maintained atthe required forward flight power, but the power available to the rotorll being now only from the outboard power units.

In stage 3, the lever 50 is moved through the gate 65 to the forwardstop, as shown in Figures 16 and 17. Simultaneously the gating bar 66interconnects the lever 50 with the outboard throttle control levers 43,44, thus progressively reducing the power and cutting off the air supplyto the rotor I l until the condition is reached (see Figures 16 and 17)of forward flight with the required propeller power, and with the rotorH in autorotation.

The changeover from forward flight to hovering may be accomplished ineither of two ways. Either (a) by starting up the centre turbine,pulling the lever 50 on to the back stop to supply air to the rotor II,and opening up the engines, or (b) pulling the lever 50 on to the backstop and opening the outboard throttles.

Figures 18 and 19' show the controls closed.

Under all conditions of engine power the propellers 19 are maintained atconstant revolutions through the medium of a known constant speed unit;however, the speed can be controlled if required by the addition of afurther lever controlling the oonstant speed unit datum.

The centre throttle control lever 53 can be operated freely throughoutits range, but, if desired, stops or gates could be provided to giveinterconnection with the air supply valve control lever 50.

By means not shown, the fuel to the rotor H is turned off and theignition switched off when the air supply valve control lever 50 ispassed through the gate 65.

We claim:

1. In an aircraft, a sustaining rotor having rotary wings radiating froma hub, at least two being independent of mechanical transmission to therotor and between each other, jets on the tips of the rotary wings, andcompressor means, driven by said power units, airconduits from saidcompressor means to said jets and to said power units, and valve meansin said conduits for selectively distributing the power from said powerunits between said propellers and said rotor, whereby said aircraft iscapable of operating as a helicopter, gyroplane or capable of beingflown employing the gyrodyne principle of distributing power between therotor and propellers.

3. A rotar wing aircraft comprising a sustaining rotor, two stub wingshaving power units mounted at the outboard ends thereof, two propellersarranged for forward propulsion of the aircraft and driven by said powerunits, there being no mechanical power transmission mechanism betweenthe power units and the rotor and no mechanical interconnection betweenthe power units themselves, each of the power units including aturbo-driven air compressor having valved connection with jets mountedat the tips of the blades of the rotor, the valved conneotions beingarranged to enable the output of the air compressors to be divisible invariable ratio between the jets at the tips of the blades and the powerunits, whereby a sufiioient propor. tion of said output may be deliveredto the jets at the tips of the rotary wings and drive the rotor forvertical flight, or the whole of said output may be delivered to theturbines to enable the propellers to be employed for forward flight, therotor then being autorotative, or said output may be distributed in anyother desired ratio between the jets at the tips of the blades and theturbines,

4. A rotary wing aircraft as claimed in claim 3 and means providingdifferential control of the pitch of said propellers and means providingdifferential throttle control of said power units, whereby control ofthe aircraft in yaw, independently of forward speed, may be obtained bysaid means providing differential control of the pitch of thepropellers, and by said means providing differential throttle control ofthe separate power units driving the propellers.

5. A rotary wing aircraft as claimed in claim 3 and means forcontrolling the pitch of said propellers whereby, in the event offailure of either power unit, the pitch of the operative propeller maybe reduced to give substantially zero thrust and the operative powerunit may be utilized to provide air flow for the operation of jets atthe tips of the rotary wings.

6. A rotary wing aircraft as claimed in claim 3, and constant speedgovernors connected with variable pitch control mechanism for thepropeller blades so arranged that when the jets at the tips of therotary wings are in use for vertical flight the propeller blades are setat substantially zero pitch and, when the flow to said jets is cut offgradually, and the flow to the turbines is increased, the pitch of thepropeller blades is increased correspondingly until the desired changeof power distribution is attained.

7 A rotary wing aircraft as claimed in claim 3, wherein the hub of therotor is provided with an air distributor casing connected to said jetsand arranged to be fed by said compressors.

8. A rotary wing aircraft comprising a fuselage, a sustaining rotor,having rotary wings radiating from a hub, attached to said fuselage,aerofoils of relatively short span extending from said fuselage, atleast two independent compressors, at least two propellers operable forforward propulsion, jet reaction units at the tips of said rotary wings,said hub being provided with a distributor, feeding ducts to saiddistributor from each of said compressors and from said distributor toeach of said jet reaction units, and at least two gas 8 turbines eachdriving one of said compressors, and at least two of said turbinesdriving said propellers.

9. In an aircraft, a rotary wing, a jet on said wing for causing saidwing to rotate by reaction, a plurality of air compressors, a pluralityof power units each driving one of said compressors with no mechanicalinterconnection between the power units themselves, a plenum chamberconnected to receive compressed air from all said compressors and todeliver said air to said jet, and an individual non-return valveinterposed between each said compressor and said plenum chamber whereby,in the event of failure of one compressor, reverse airflow thereto doesnot occur.

10. In an aircraft, a rotary wing, reaction jet means on said wing fordriving said wing, two air compressors connected to supply compressedair as working fiuid to said jet means, power units with no mechanicalconnection therebetween, connected respectively to said compressors todrive same, and a propeller driven by one only of said power units.

JAMES ALLAN JAMIESON BENNETT. ARCHIBALD GRAHAM FORSYTH.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,483,480 Stalker Oct. 4, 1949 2,518,498 Schulte Aug. 15, 19502,540,190 Doblhoif Feb. 6, 1951 FOREIGN PATENTS Number Country Date259,295 Switzerland June 16, 1949

